Modern electronic circuits or systems often includes several blocks of circuitry. The blocks of circuitry provide some of the overall functionality of the circuit or system, such as data or signal processing, communication, computation, control functions, and the like. Each block may receive a number of inputs, such as data, general signals, and control signals. Further, each block may provide a number of outputs, such as data, general signals, and status signals.
Some of the blocks of circuitry perform functions that use one or more reference signals. The reference signals may provide timing (e.g., synchronization) for various functions. For example, reference signals may be used to time various events with respect to other events, e.g., synchronize two events. Examples of reference signals include clock signals, local oscillator signals, etc. Reference signals may be produced in a number of ways. Examples include resistive-capacitive (RC) oscillators, crystal oscillators, inductive-capacitive (LC) oscillators, and the like.